Lattice instability in ZnSe:Ni crystal

Abstract

Ultrasonic experiments, done on ZnSe:Ni crystal with the dopant concentration 5.5 × 10 19 cm -3 , revealed precursor phenomenon in the form of lattice softening at temperatures significantly exceeding the temperature of structural transition (T c = 14.5 K). It proved to be that the order parameter of the transition was associated with the shear deformation ε 4 . Investigation of thermal conductivity (κ) in the same temperature region pointed out that the Jahn-Teller (JT) effect could be responsible for the anomalous behavior of κ(T) and lattice instability.